License library / Permissive software
zlib License
Use for any purpose, including commercial, and alter and redistribute freely, as long as you do not misrepresent the origin, mark altered versions, and keep the notice in source distributions.
SPDX Zlib Version zlib Official text
Uses at a glance
| commercial use | Permitted |
|---|---|
| production deployment | Permitted |
| modification / derivatives | Permitted |
| redistribution | Permitted |
| sublicensing | Not documented |
| AI model training | Needs human review |
| inference-time use (RAG, prompts, generation) | Permitted |
Why some uses need review
AI model training. The license grants broad rights but attaches conditions (such as keeping notices) to copies and adaptations. Whether a trained model, or its output, is a copy or adaptation that carries those conditions is legally unsettled, and in some places training may fall under an exception such as fair use. A human reviewer should confirm this use for your case.
Duties
- license notice
- state changes
- no misrepresentation
Notes
- Sublicensing is not mentioned, so it is not treated as granted.
Resources under this license
No resource in the registry is published under this license yet.
For agents
curl -s https://www.rightshold.com/v1/licenses/check -H 'content-type: application/json' \
-d '{"license":"Zlib","intended_use":{"commercial_use":true,"deployment":true}}'Reading version 2026-10-09 by the Rightshold rights desk; reference hash ea6d061f0eb1511fdc2418bb4420c2a33809fd7de9a86bd157973a330b54d307 identifies this license version. The license text governs; this is not legal advice.